In recent years, a power control apparatus, for the purpose of totally managing energy in a consumer and such as relieving a load of a power grid and energy saving, has begun to be introduced. The power control apparatus is called an EMS (Energy Management System). Also, various types of power control apparatuses are proposed as for various consumers and for example, among such power control apparatuses, which intended for a house is called a HEMS (Home Energy Management System).
For the power control apparatus performs an appropriate energy management, it is necessary to transmit a command to execute processing at optimum timing to equipment and control the equipment more minutely.
Accordingly, art that equipment notify a power control apparatus of time until the equipment become to be a receivable state again after a command (a command for instructions) is transmitted to the equipment by the power control apparatus is disclosed (for example, Patent Literature 1). Since the power control apparatus can grasp next receivable timing of the equipment, the transmission of unnecessary command can be suppressed, by applying the art.